1. Field of the Invention
The present invention relates to a packaging bag for secondary packaging configured to package and transport containers having infectious substances such as causal organisms or specimen materials stored therein safely.
2. Prior Art
In order to transport (by air transport) infectious substances, being categorized into Category A and Category B depending on the types of the corresponding infectious substances on the basis of IATA Dangerous Goods Regulations, it is made mandatory to transport with packaging infectious substances in both categories triply according to standards defined in Infectious Diseases Control Law and the like. As a primary package, for example, containers such as test tubes, blood drawing tubes, cups, or the like which can be hermetically sealed with a plug member are employed. As a secondary package, for example, resin bag members (pouches) configured to wrap the primary packaging containers with a cushion material, formed into a bag shape having hermeticity and water resistance, and meeting standards defined in Infectious Diseases Control Law and the like such as being capable of enduring temperatures between −40° C. and 55° C. and bearing a pressure difference of 95 kPa or larger with respect to an internal pressure thereof are employed. As a tertiary package, exterior containers configured to accommodate the secondary packaged substances, for example, having a relatively robust structure having water resistance, shock resistance, and heat insulating properties are employed.
As a known example of the packaging container of this type, for example, there is a transport container configured to package an infectious substance in a container and accommodate and transport the prepared package including an exterior container and a heat-insulating container matching the exterior container and configured to be loaded therein so as to be freely unloadable and accommodate the package, wherein the exterior container includes a cylindrical body formed of thick paper material such as a corrugated cardboard into a square shape having a desired size in cross section, a bottom lid portion formed of a flap continuing from one end of the body so as to be freely foldable, and an upper lid portion formed of a flap continuing from the other end of the body so as to be freely foldable, the heat insulating container includes a cylindrical body portion opening on both ends, a bottom lid portion configured to close up the opening at one end of the body portion, and an upper lid portion configured to close up the opening at the other end of the body portion, the cylindrical body portion is formed of foam paper having predetermined width and length, includes a rectangular panel member having a desired thickness, and is configured to be formed into a square shape in cross section by being folded along bending portions provided in parallel to the width direction thereof at predetermined portions so as to bring both ends of the panel member into abutment, the bottom member includes a square bottom plate formed of a material having heat insulating properties and shock absorbing properties and formed into a size meeting an end surface of the opening of the body portion at the one end, and an engaging device configured to disengageably engage the bottom plate with the opening of the body portion, the upper lid portion includes a square top plate formed of a material having heat insulating properties and coherent properties and formed into a size meeting the end surface of the opening of the body portion at the other end, and an engaging device configured to disengageably engage the top plate with the opening of the body portion (see Japanese Patent Utility Model No. 3153217).
The transport container described above is a tertiary packaging exterior container and allows transport under temperature control such that content accommodated in the heat-insulating container (packaged infectious substance) is kept cooled at a predetermined temperature. Since the plate member which forms the cylindrical body portion of the heat-insulating container can be stored in a stack, a storage space can be reduced. The bottom lid portion and the upper lid portion can also be stored in a stack. In addition, since the exterior container can be folded into a flat profile, storage in a stack in the same manner as described above is possible. Then, the transport containers can be used by being assembled when needed. Since a cushioning function (shock absorbing function) is provided, the substance accommodated therein (content) can be protected from external influences such as physical damages.
In this known example, an example of a secondary packaging container is disclosed. The container in this example employs a plastic bag (pouch). The plastic pouch is formed by polymerizing two plastic sheets and sticking peripheral edges on top, bottom, left, and right in an air-tight manner by heat sealing or the like and is configured in such a manner that, for example, a loading-and-unloading port is formed by incising one of the plastic sheets on one side at a portion near an upper end portion so as not to reach both side edge portions and a fastener is attached inside the loading-and-unloading port to allow opening and closing thereof, the fastener is made up of a projecting engaging strip and a depressed engaging strip formed of resin, and the projecting engaging strip and the depressed engaging strip are engaged into tight contact with each other by being pressed from above the sheets and disengaged from each other by being applied with a force of separating the sheets. Subsequently, the container is hermetically sealed by sticking an adhesive-backed tape to the loading-and-unloading port in a state in which the projecting engaging strip and the depressed engaging strip are engaged into tight contact with each other.
Incidentally, the secondary packaging pouch formed of plastic sheets in the known example described above, since the loading-and-unloading port is formed by incising one of the plastic sheets on one side so as not to reach the both side edge portions and, in addition, the resin fastener is attached inside the loading-and-unloading port, there are problems not only in that the loading-and-unloading port is too small to load and unload the packaged substance easily so that handling and workability are hindered, but also only in that even though the loading and unloading port is maintained in the hermetically sealed state by an engaging force between the projecting engaging strip and the depressed engaging strip of the resin fastener and an adhesive force of the adhesive-backed tape in an actual use, when the internal pressure reaches a standard pressure of 95 kPa or higher by expansion of interior air due to the temperature variations, the corresponding pressure acts on the adhesive tape directly via the fastener and the plastic sheets are expanded entirely by the expansion of the pouch, whereby the adhesive tape is peeled off by the direct pressure action and the expanding action and then the engaging strips of the fastener is separated to open the loading-and-unloading port, so that the preset standard pressure difference defined in the Infectious Diseases control Law and the like cannot substantially be supported.
As described above, the secondary packaging plastic sheets or the film-made pouch in the known example described above takes a double hermetically sealed state using an engaging force of the fastener and an adhesive force of the adhesive tape. However, in this configuration, the hermetically sealed state cannot be maintained by separation of the adhesive tape and disengagement of the engaging strips of the fastener by direct application of a pressure increased by expansion of air in the interior of the pouch due to temperature variations and the expanding action due to the expansion of the pouch, and hence reliability is not sufficient for being used for transporting the infectious substances.